Higher secretion of T-helper 1 (Th1) cytokines (TNF-a, IFN-γ) after in vitro T-cell stimulation was linked to a lower risk of UTI (HR [95% CI]: 0.79 [0.62–1.01], 0.64 [0.40–1.04]), whereas Th2 cytokines (IL-4, IL-5) revealed opposite associations (HR [95% CI]: 1.56 [0.74–3.27], 1.59 [0.99–2.58]). This evidence concerns the gene TNF and bacterial urinary tract infection.